The field of this invention relates to shock absorber struts and more particularly to a very large heavy strut means where in the inner and outer tube assemblies can rotate independently in at least two different directions and to a method of replacing one bearing set thereof without removal from the truck.
Heavy off-road haulage trucks which are designed to carry loads in the range of from 35 to 220 tons because of necessity designed to employ some sort of shock absorber strut means. Such strut means is as apparent are massive in size, for example, a strut means for a 150 ton hauler weighs in the range of 1,100 to 1,200 lbs. and is approximately 71/2 ft. long and 14 inches in diameter. A substantial number of such struts employ hydraulic principles to absorb the shock. Characteristically, they leak and require servicing. Invariably they must be removed entirely from the vehicle and taken to a repair shop, for example, for servicing, which, as appreciated because of their size, is very difficult. Another problem, and herein depending upon the shock absorber employed, whether it be hydraulic or of the elastomer nature, it can be subject to varying degrees to contamination. For example, in the mines very often there is substantial amounts of sulfur gases which attack elastomer material. Where dirt roads are employed, the fine powdered dust invades the moving parts and acts like a grinding material. Another difficulty which may cause premature failure of the shock absorber, depending on the type employed, has to do with the mechanism which holds the inner and outer tube assemblies together. As is apparent, the shock absorber strut should be able to not only move in both directions along its major axis but should have the freedom to rotate as well. That is, because of road conditions the inner tube assembly may move along the major axis and rotate to the right while the outer tube assembly was also moving along the major axis but rotating to the left. This action is particularly destructive to those type of struts which employ a cam and cam slot to hold the two assemblies together.
It is, therefore, a prime objective of the invention to provide a shock absorber strut means which is sealed against exterior contamination, can in part be serviced without removal from the vehicle and allows for both horizontal and rotational movement of the parts in different directions along the main axis. Yet another objective is the provision of a shock absorber strut which employs a compressible solid material and thus is not subjected to leakage.